Air-brake.



A. A. sT. CLAIR. AIR BRAKE APPLICATION FILED NOV.26 1907. 899,844. 1

Ptented Sept. 29, 1908..

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AIR BRAKE.

APPLIOATION FILI-:AD Nov. ze, 1.907.

Patented Sept. 29, 1908.

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. AIR BRAKE.

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Patented Sept. 29, 1908.

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- AIR BRAKE.

- APPLIoATIoN FILED No?. 26, 1907. 899,844.

Patented Sept. 29, 1908.

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AIR BRAKE. y I APPLICATION FILED Nov, 26, 1907.

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Patented Sept. 29,' 1908.

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AIP. BRAKE. -APPLIOATION FILED NOV. 26, 1907.

Patented Sept. 29, 1908.

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@Mommy UNITED STATES PATENT OEEIO AUGUSTUS A. sT. CLAIR, oF INDIANAPOLIS, INDIANA, ASSICNORTO ST. CLAIR AIR BRAKE COMPANY, OE INDIANAPOLIS, INDIANA, A CORPORATION OP INDIANA.

` AIR-B BAKE No. 899,844. v

Specification of Letters Patent.

Patented Sept. 29, 1908.

To all whom it may conc/ern.'

Be it known that I, `AUeUSTUS A. ST. CLAIR, a citizen of the United States, residing at Indianapolis, in the county of Marion and State of Indiana, have invented certain new andvuser'ul Improvements in Air-Brakes, of which the following is a specification.

The obj ect of my invention is to produce an improved automatic valve mechanism for air brakes, comprising means for quickly reducing the train line pressure, a predetermined and fixed amount, at each individual car immediately upon the primary reduction at the engineers valve.

Further objects of my invention are to produce a brake controlling valve structure which shall at all times be under complete control from' the engineers valve; which shall permit a graduated brake release, and which permits a local train line reduction to atmosphere.

A further object of my invention is to provide improvements in the valve mechanism especially designed for use in conjunction with that type of air brakes described and Claimed in my Patent No. 360946 issued July 23, 1907, together with such improvements in details of construction as shall be hereinafter pointed out.

The accompanying drawings illustrate my inve tion: y

Figure 1 is a partial vertical section of' an air brake cylinder and valve mechanism embodying my invention as applied to an air brake of the type just mentioned; Fig. 2 an axial section of my improved valve mechanism in full release and charging position;

Fig. 3 a similar view with the parts in running position Fig. 4 a similar view with the parts in full first service position; Fig. 5 a similar view with the parts in full second-service position 5 Fig. 6 a similar view showing the parts in emergency position; Fig. 7 a transverse section on line 7-7 of ig. 3; Fig. 8 a transverse section on line 8-3 of Fig. 3; Fig. 9 a perspective view of the valve ring showing the several ports thereof; Fig. 10 a fragmentary perspective ol' that portion of the valve chamber in which the several ports are formed; Fig. 11 a detail section on line 11 of Fig. 7 with the parts in full release position; Fig. 12 a view similar to Fig. 11 with the parts inrunning position; Fig. 13 a transverse section Showing the port relations in full first-service position for transfer of pressures for the local reducing of the train line pressure to the fixed predetermined amount. Fig. 14 a transverse section through the pocket-port in irst-servioe position. Fig. 15 a similar view showing connections between the pocket and atmosphere in running position. Fig. 16 a longitudinal section with the ports in initial graduated release position. Fig. 17 a perspective transparency showing the port arrangement for local train line exhaust to atmosphere.

In the drawings 20 and 21 indicate the primary and Secondary Chambers of the brake cylinder with the piston 22 mounted between the same and springs 23 mounted in chamber 21 and adapted to act upon piston 22 and force the same to braking position, the piston carrying a piston rod 24. A passage 25 forms, through the medium of the valve mechanism to be described, a connection between the `chambers 20 and 21..

Thus far the structure is identical With that shown in my patent already mentioned and in general the valve mechanism for controlling the air pressures Within the two chambers 20 and 21 is Similar to that shown in my patent already mentioned but diHers therefrom in material details. The end of chamber 20 is closed by head 26 and inthis head is formed a cylindrical valve chamber 27, the outer end'of which is closed by a head 28. Mounted in chamber 27 and fitting the same is a valve ring 29 which lies in a circumferential groove 30 formed in the periphery of a piston valve 31, the axial dimension of said groove being a little greater than the axial dimension of the ring and the radial dimension of the groove being greater than the radial thickness of the ring, for a purpose Which will appear. The piston valve at its outer end is packed at 32. Secured in ring 29 is a pin 33 which lies parallel with the axis of the ring and extends laterally through the adjacent flange of the piston valve and also through an opening 34 through the inner lhead of chamber 27 so as to hold both the ring and piston-valve against rotation within the chamber 27 Whilepermitting free axial movement.I Mounted in the inner head of the piston valve 31 is a buffer plunger 35 which is normally held projected from the inner end of the' piston-valve by means of a spring 36 which may conveniently have a 'force on the buffer plunger of say 5 lbs. to the square inch of piston valve area. Free communication between the inner end of chamA ber 27 and chamber 20 is had through suitable openings 37 through the head of the inner end of chamber 27 and a passage 33 provides `free communication through plunger into the interior of the piston valve and from thence through passages 39 into groove 30 between the bottom of said groove and the inner wall ol' ring 29. Mounted in the outer head of the piston valve 31 is a buiier plunger 40 which is normally held projected by a spring 41 of substantially the same strength as spring 36. Formed in ring 29 is a passage 42 which, at one end, opens into the outer end of ring 29 and at its other end opens into the periphery ol said ring in order to register at times with a port 43 formed through the bushing 27 which forms the wearing wall of chamber 27. Formed in head 26 is a passage 44 which extends between port 43 and passage 25. Formed in head 26 is a passage 45 which leads to atmosphere and this passage communicates with the interior of chamber 27 through a port 46 formed through bushing 27 Formed in the periphery of ring 29 is a pocket 47 adapted, at times, te connect ports 43 and 46, said pocket having a small extension 47 at its inner end to serve in obtaining the graduated release which will be explained later. Extending radially through ring 29 is a passage 50, the outer end of which is adapted to be brought into register with a port 5l 'formed through bushing 27 and communicate with a passage 52 extending axially beneath said bushing, and at its outer end communicating with the port 53 'formed through bushing 27 and always in communication with the outer end of chamber 27. The outer end of passage at its rear side is provided with a slight restricted extension 50 which, in running positions of the parts maintains a small leakage connection between the outer end olf chamber 27 and the chamber 2() of the brake cylinder through passage 52, in order to permit gradual and continuous maintenance of equal pressures in the train line and the primary pressure chamber 20 during the running. The inner end of passage 42 is extended in the periphery of ring` 29, as shown at 42, Fig. 9, in order to register with port 51. when the parts are in full second service position and thus locally exhaust train line pressure in the outer end of chamber' 27, and adjacent train line of the car.

For the purpose of quickly reducing the train line pressure to a iirst service condition, without the necessity of waiting for such reduction through the engineers valve, Iform in each head 26, a train line exhaust pocket which has a capacity to receive from the train line of the particular car on which the apparatus is carried such volume of air as will reduce the pressure from running pressure to first service application pressure, this capacity being, for the present commercial structures, about 4() cubic inches, and said port 60 communicates by a passage 6l with a port 62 Aloi-med through bushing` 27. 'lhe port 62 is substantially in alinement with port 5l and formed in the periphery ol' ring 29 is a pocket 63 which, in running position, lies immediately adjacent thev two ports 5l and 62 so that the iirst movement ol ring 29 toward lirst service position jl'rom running position will cause pocket 63 to l'orm a communication between ports 62 and 5l and permit the train line pressure within the outer end of chamber 27 to )ass through passage, 52 and thence into pocliet 66.

Formed in the periphery ot ring 29 'is a pocket 64 adapted to register with port 62 when the ring 29 is in ruiming or l'ull release position. The reduction. in pressure ol'V the train line of a forward car into its pocket 6() immediately causes a reduction in the train of the next car to the rear enough to move its valve and immediately permit reduction ol the train line pressure ol" said rear ear into its pocket so that the action elt the valves ol' successive cars to the rear takes place with great rapidity. ln other words, there is an automatic serial reduction in an unlimited number of cars by a very slight reduction through the engineers valve which may immediately be thrown to lap position. vheading from said pocket 64 to pocket 47 is a passage 64 through which the pressure in chamber 60 may exhaust to atmosphere when the parts have been brought back to their l'ull release or ruiming position.

Formed in head 28 is a chamber 65 into which the train line pipe 66 leads, and said chamber has free communication with the outer end of chamber 27 Formed. in chamber 65 is a medial partition 67 through which suitable openings 68 are 'l'ormed to provide free communication through the partition, and mounted centrally in said partition is a bushing 69 having an annular chamber 76 which communicates with the passage 7l which communicates with the pas age 72 which enters passage 44 and thence communicates with passage 25. The outer end of the annular chamber 7() opens into the outer end of chamber 65 and the valve 73 is provided to normally close communieation between chamber 65 and the annular' ehambe r 70. Valve 73 is provided with a stem 74 which extends through bushing 69 and lies in the path .of movement ol the bull'er plunger 46. A spring 75 serves to normally hold valve 73 on its seat, said springhaving a. strength greater' than. spring 4l, preferably about l() pounds to the square inch` oi pistou valve area. Formed in the outer end ol' bushing 27 are some passages 3() which extend axially into said bushing a distance a little greater than the axial thickness ol the outer head of the piston valve so that when .l (lll .with that portion of groove 30 lof the piston valve beyond the outer end of ring 29, as clearly shown in Fig. 6. The passages 30 at their outer ends communicate, through grooves 81 formed in ber 65.

The operation is as follows: Assuming the parts to be under no air pressure, spring 23 will move piston 22 to the eXtreme of its movement, as indicated in dotted lines of Fig. 1. Train line pressure introduced through pipe 66 will pass into chamber 65 thence through passages 68 into the outer end of chamber 27 and, acting upon the outer end of the piston valve 31 will move said piston valve andthe valve ring 29 to the positions shown in Fig. 2, Whereplunger 35 is forced back into the piston valve and spring 36 compressed. In this position pocket 47 forms alfree communication between ports 43 and 46 so that chamber 21 is in free communication with the atmosphere;

head 28, with `cham- Apassage 50 is also in full communication with port 51 so that the train line pressure may pass from the outer end of chamber 27 through the port 53, passage 52, ort 51, passage 50, the annular space 30 insi e of ring 29, passages 39, 38 and 37,into chamber 20. At the same time pocket 64is in register with port 62 so that chamber 60 is in free communication with the atmosphere through pocket 47 and passage 45. When the pressure within chamber 20 has reached an amount differing from train line pressure by a little less than the strength of spring 36, said spring operating through plun er 35will automatically shift the iston va ve and valve ringto the positions siiown in Fig-3, where passage 50 is shifted with relation to portA 51 (as shown in Fig. 12) where the leakage passage 50 overlaps port 51. In this position there is suflicientgradual leakage through passage 50 and passage 50 from the outer end of chamber 27 into chamber 20 to gradually permit an equalization of pressures so that,

the pressure .Within chamber 20 within a comparatively short time becomes equal to train line pressure. y

For an ordinary` servicev application the engineer will open his valve and reduce train line pressure enough to cause the pressure within the inner end of chamber 27' ofl thel first brake mechanism next the engine lto shift the piston valve and its ring to the position shown in Fig. 4, and immediatelythrow his valve to lap. Upon this action on the first air brake mechanism of the train, the pocket 63 or the valve ring thereof will bridge between the two ports 51 and 62 and this permit a portion of the train line pressure of that f -particular car to pass quickly through passages 53, 52 and 51, pocket 63, port 62, and

passage 6l into pocket 60, and this action of the first brake mechanism will cause suc ce sive actions of the brake mechanisms of the successive cars much more rapidly than would be possible if the entire train line pressure reduction had to be accomplished through the engineers valv'e. The engineer need hold his valve open for iirst service position only enough to obtain the described action of the first car, the successive cars reducing train line pressure into preceding car train lines and their respective pockets 60. With the parts in position shown in Fig. 4, pressure from chamber 20 passes n back through passages 37, 38, 39 and 30 to the outer end of ring 29 and from thence to the L-shaped passage 42 and port 43 into passage 44 and thence through passage 25 into the spring chamber 21, this movement of pres sures continuing until the pressure in the inner end of chamber 27 is a trifle less than the reduced train line pressure in the outer end of chamber 27, whereupon the piston valve 31 is shifted to the left in Fig. 4, to the position shown in Fig. 13 thus closing the right hand end of passage 42 and preventing further movement of pressures from chamber 20 into chamber 21.

1t is to be remembered that, in order to insure the movement of any valve which is subjected to pressures upon both sides, unless that valve be of the diaphragm type, a reduction of pressure upon one side of the valve must be not only sufficient in amount but must be produced with suchrapidity that leakage past the valve will not be as fast The as the speed ofpressure reduction. function of the pocket 60, therefore, is to provide a means of reducing train line pressure a fixed and predetermined amount and with such speed as to insure the movement of the valve from running position to first service position, so that a connection will be insured which will cause a proper application of the brakes. 1t is to be understood, however, that in order to obtain the best and most sensitive results, the capacity of the pocket 60 should not be enough to reduce train line pressure to such an extent that there will be a heavy application of brakes upon the slight reduction through the engineers valve necessary to cause the use of the local pocket. In other words, the size of the ports which permit communication between pocket 6() and train line is as vessential as the size of the pocket for the reason that it is speed of reduction of train line pressure which is more to ,be desired than quantity, the actual emergency application. lt will therefore be seen that, by the'arrangement shown, I am able to insure a uniform movement of all of the brake mechanisms of an unlimited number of cars. A further slight reduction of train line pressure through the engineers valve will cause the piston valve to move again to the position shown in Fig. 4, whereupon there will be a further reduction of pressure within chamber 20, and consequently an increase of air volume in chamber 21. Upon the resumption of train line `pressure the parts will move to the position shown in Fig. 2, thus exhausting the pressures from chambers 21 and 60, in the manner already described. the resumed train-line tion shown in Fig. 16 where there will be a gradual outlet of pressure from chamber 2l through extension 47 of pocket 47 to passage 45 and atmosphere. Consequently the increasing train-line pressure will pass through the length of the train so as to shift the valve to slow release position to exhaust chambers 21 before any of the train line increase passes into the chambers 20. of forward ears. After all pressure has been exhausted from chamber 2l to atmosphere (the speed depending upon the speed of increase of train line pressure) then upon further increase of train line pressure spring 36 is further compressed and passage 50 comes into register with port 51 so that pressure is gradually admitted into the primary pressure chamber 2O in opposition to springs 23 thus continuing the gradual release of the brakes. rl`he engineer may with great nicety graduate the release and adjust the braking force to the gradually decreasing speed of the train. It will of course be understood that the brakes may be released with great rapidity by rapidly increasing the train line pressure.

The iirst service position will be utilized until the pressure within chambers 2() and 21 are equalized, at which time the full force of the springs 23 will be exerted as a braking force. If a further braking force is desired, the engineer will permit a free train line reduction through his valve, whereupon the parts will move toward the position shown in Fig. 5. In this position passage 42 is brought into partial register with port 46. Pocket 63 is carried beyond register with ports 51 and 62, and plunger 40 will be pressed back into the piston valve by stem 74, the spring being stronger than the spring 41. In this position the remaining pressure, or a portion thereof7 in chamber 20, will pass through passage 42 into passage 45, and thence to atmosphere but, so soon as the pressure within chamber 20 is reduced to a trifle less than the combined remaining train line pressure and pressure of spring 41, the piston valve will be automatically shifted to the left from the position shown in Fig. 5 until it closes the right hand end of passage 42 and prevents further The valve will first be driven by pressure to the posireduction of the pressure in. chamber 20. The pressure within chamber 2() may, however, be entirely withdrawn to atmosphere. by proper manipulation of the engineer-s valve. The air pressure previously inserted in chamber 21 will assist the springs as an additional braking force. Increase, of train line pressure will carry the parts back to position shown in Fig. 2 with a consequent release ol' the brakes as already explained.

If an emergency appliczuion is desired, the engineer will suddenly reduce his train line pressure through the emergellcy opening, and the piston valve will then travel suddenly to the position shown in Fig. 6, with sullieient force behind it, through the pressure in chamber 20, to compress spring 75 and unseat valve 73, whereupon the pressure within chamber 20 may pass immediately through passagesS() and 81 in chamber 65, and thence through chamber 7() and passages 7 1. and 72 into passage 25 and into chamber 21, causing an instantaneous equalization of air pressure between the train line pressure chamber 2() and spring chamber 21, at which time spring 75 seats valve 73. 'lhen air passes `from chamber 20 through passage 42 to atmosphere. Train line pressure also passes to atmosphere through 53,52, 51, 42, 42 and 45.

As soon as the pressure within chamber 2() is reduced to the combined remaining train line lpressure and the pressure of spring 75, the parts will assume the position shown in Fig. 5 and the force exerted on the brakes will be the second service force, an action of the emergency parts merely decreasing the time in which the force of second service appl' :ation is obtained.

I claim as my invention:

l. In an air-brake mechanism, the combination, with a double ended cylinder, a brake-controlled piston mounted therein to form primary and secondary pressure chambers, a spring tending to drive the piston to brake-setting position, a traineline-exhaust pocket, and a transfer passage forming a. communication between the two pressure. chambers; of a valve mechanism for controlling the brake-operating piston, said. f'alve mechanism comprising the following parts, a.

valve cylinder communicating with the trainline at one end and` at the other end with the primary pressure chamber, said valve cylinder having a port communicating with the transfer passage, a port co1unumicating with atmosphere, a supply port communicating with the train line end of the cylinder and a, port leading to the train-lineexhaust pocket, a piston valve mounted in said valve eyli nder and comprising a head member and a ring member, said ring member having a limited axial play in the head member and said ring member having a passage forming a communication between its outer end and its circumference in position to be brought into lll) lll() register with the transfer passage port, a

' pocket in the circumference of said ring j with its interior and at the circumference of 'responding direction.

the ring-adapted to register with the trainline port, and also a pocket adapted to conf nect the train-line-exhaust pocket with atmosphere, and also a passage adapted to connect the said pocket with the train-line.

2. In an air-brake, a double-ended brake cylinder having a transfer passage between its ends, a brake-operating pistonmounted in said cylinder, a spring yieldingly urging said piston to brake-setting position, and a train-line, of a valve subject to train-line pressure and pressure in the initial end of the brake cylinder, said valve controlling communication between train-line and the initial end of the cylinder, between the initial .8nd of the cylinder and the transfer passage, and between atmosphere and both the transfer passage and the initial end of the cylin-V der, and yielding means for yieldingly resisting movement of said valve inone direction.

3. In an air brake, a double-ended brake cylinder having a transfer passage between its ends, a brakeeoperating piston mounted in. said cylinder, a spring yieldingly urging said piston to brake-setting position, and a train-line, of a valve subject to train-line pressure and pressure in the initial end of the brake-cylinder, said valve controlling communication between train-line and the initial end of the cylinder, between the initial end of the cylinder and the transfer passage, and between atmosphere `and both the transfer passage and the initialend of the cylinder, and a pair of spring pressed plungers lprojected from opposite ends of said valve and adapted to engage the casing at the o posite ends of the travel of said valve to yie dingly resist further movement thereof in the cor- 4. An air brake, comprising a cylinder and piston, a spring for driving the piston in .one direction, and a train-line for supplying pressure to the initial end of said cylinder in opposition to the spring, a valve arranged between the train-line' and initial end of the cylinder, said valve carrying a port-controlling member, and a spring plunger for normally yieldingly urging the valve from full open position toward closed position, whereby a graduated introduction of pressure froml tram-line to the initial end of the cylinder is insured. y

5. An air 'brake comprising a cylinder and piston, a spring for driving the piston in one direction, and a train line for supplying pressure to the initial end of said cylinder in opposition to the spring, a valve arranged between the train-line and initial end of the cylinder, said valve carrying a port-controlling member, and a s ring plun er carried by the valve for normal y yielding y urgin the valve fromfull open position toward c osed position, whereby a graduated introduction of pressure from train-line to the initial end ofthe cylinder is insured.

6. An air brake comprising a cylinder and piston, a spring'for driving the piston in one direction, and a train-line for supplying pressure to the initial end of said cylinder in opposition to the spring, a valve arranged between the train-line and initial end of the cylinder, said valve carrying a port-controlling member, and a pair of oppositely acting 1 spring plungers operating to yieldingly limit the throw of the valve at its opposite ends, for the purpose set forth.

7. An air brake comprising a cylinder' and piston, a spring for driving the piston -in one direction, and a train -line for supplying pressure to the initial end of said cylmder in opposition to the spring, a valve arranged between the train-line and initial end of the cylinder, said valve carrying a port-control ling member, and a air of oppositely acting spring plungers carried by the valve and operating to yieldingly limit the throw of the valve at its opposite ends, for the purpose set forth.

8. In an air brake mechanism, the combination, witha double-ended cylinder having a transfer passage between its ends, a brake-V operating piston mounted in said cylinder, a spring urging said piston to bralresetting position, a train-line for su plying pressure to the initial end of the cy inder, and a trainline-exhaust pocket adapted to receive pressure from the train line, of a valve subject to train-line ressure on one side and pressure from the mitial end of the cylinder on the other side, said valve carrying means for connecting the train-line with the pocket, for connecting the initial end of the cy inder with the transfer' passage, for connecting the transfer passa e with atmosphere, for connecting the initia end of the cylinder with atmosphere, for connecting the train-line with the initial end of the cylinder, and for connecting the pocket with atmosphere.

9. In an airbrake mechanism, the combination, with a double-ended cylinder having a transfer passage between its ends, a brakeoperating piston mounted in said cylinder, a spring urging said piston to brake-setting position, a train-line for su plying pressure to the initial endof the cylinder, and a trainline-exhaust pocket adapted to receive pressure from the train-line, of a valve Subj ect to train-line pressure on one side and pressure from the mitial end of the cylinder on the V other side, said valve carrying means for connecting the train-line with the pocket, for

connecting the initial end of the cylinder with the transfer passage, for connecting the transfer passage with atmosphere, for connecting the initial end of the cylinder with atmosphere, for connecting the train-line with the initial end of the cylinder, and for connecting the pocket with atmosphere, and means controlled by the movement of said valve for connecting the train-line directly to the transfer passage.

l0. In an air brake mechanism, the combination, with a double-ended cylinder having a transfer passage between its ends, a brakeoperating piston mounted in said cylinder, a spring urging said piston to brake-setting position, a train-line for supplying pressure to the initial end of the cylinder, and a trainline-exhaust pocket adapted to receive pressure from the train-line, of a valve subject to train--line pressure on one side and pressure from the initial end of the cylinder on the other side, said valve carrying means for connecting the train-line with the pocket, for connecting the initial end of the cylinder with the transfer passage, for connecting the transfer passage with atmosphere, for connecting the initial end of the cylinder with atmosphere, for connecting the train-line with the initial end of the cylinder, and for connecting the pocket with atmosphere, and means for yieldingly opposing the movement of said Valve at the ends of its throw.

ll. In an air brake mechanism, the combination, with a double-ended cylinder having a transfer passage between its ends, a brakeoperating piston mounted in said cylinder, a spring urging said piston to brake-setting position, a train-line 'for supplying pressure to the initial end of the cylinder, and a trainline-eXhaust pocket adapted to receive pressure from the train line, of a valve subject to train-line pressure on one side and pressure from the initial end of the cylinder on the other side, said valve carrying means for connecting the train-line with the pocket, for connecting the initial end of the cylinder with the transfer passage, for connecting the transfer passage with atmosphere, for connecting the initial end of the cylinder with atmosphere, for connecting the train-line with the initial end of the cylinder, and for connecting the pocket with atmosphere, means controlled by the movement of said Valve for connecting the train-line directly to the transfer passage, and means for yieldingly opposing the movement of said valve at the ends of its throw.

l2. Inan air-brake system, the combination, of a train line, pressure controlled brake-operating means, a valve subject to train-line pressure, said vvalve controlling an outlet from a pressure chamber of the presmovement of said valve to a position of less than maximum opening from the pressure chamber, said yielding means acting in opposition to train-line pressure on the valve, whereby increasing train-line pressure will overcome said yielding means and serve to gradually increase the outlet from the pressure chamber.

13. ln an air-brake system, the combination, of a train line, a brake-controlling piston and a pressure chamber within which said piston is mounted., a Valve subject to train-line pressure, said valye and n'essure chamber having coi'iperating relatively-graduated discharge passages, and yielding means for initially limiting the movement of said valve by increased train-line pressure to a position of less than maximum release of pressure acting on the brake-controlling pisvton, whereby further incrase of train-line pressure will overcome said. yielding means and move said valve toward the maximum outlet for said pressure chamber.

14. ln an air-lnalie system, a brake cylinder and a brake-controlling piston mounted therein to 'form prima-rpv and secondary pressure chambers on opposite sides of said piston; a spring for normally urging said pist on toward brake-operating position; a train line for supplying pressure to the primary pressure chamber in opposition to the spring; Valve subject to train-line pressure on one side and to primary-chamber pressure on the opposite side, said valve having means controlling communication between the train line and the primary chamber, and between the primary chamber and atmosphere, and between the primary and secondary chambers, and between the secondary chamber and atmosphere; and a yielding means arranged to yieldingly oppose imwement of the said valve by increased. train-line pressure -from a position of small sccomlary-chamber exhaust toward increased secomlary-chainber exhaust.

l5. In an air-brake system, a brake cylinder and a brake-controlling piston mounted therein to form primary and secomlarv pressure chambers on opposite sides of said piston, a spring 'for normally urging said piston toward brake-operating position; a train line for supplying pressure to tlieprimary pressure chamber in opposition to the spring; a` valve subject to train-line pressure on one side and to primary-chamber pressure on the opposite side, said valve having means eontrolling communication between the train line and the primary chamber, and betweenthe primary chamber and atmosphere, and. between thel primary and seeomlary chambers, and between the secondary chamber and atmosphere; and a spring plunger carsure-controlled brake-operating means, and i ried by said valve and arranged to yieldingly a yielding means normally limiting the l oppose movement of said, valve by increased lll() lll) ` toward brake-operating position; a train "sure chambers on opposite sides of said pisa valve subject to train-line pressure lthe primary' chamber and atmosphere, and

a valve subject to train-line pressure on one side and to primary-chamber pressure on the opposite side, said valve having means controlling communication between the train line and the primary chamber, and between the primary chamber and atmosphere, and between the primary and secondary chambers, and between the secondary chamber and atmosphere; a spring plunger carried by said valve and arranged to yieldingly oppose movement of said valve by increased trainline pressure from a position of small secondary-chamber exhaust toward increased secondary-chamber exhaust, and a spring plungercarried by said valve and arranged to yieldingly oppose movement of the valve by primary-chamber pressure to the position oi' primary-chamber exhaust to atmosphere.

19. 1n an air-brake system, a brake-cylinder and a vbrake-controlling piston mounted therein to form primary and secondary pressure chambers on opposite sides of said pist0n; a spring for normally urging said piston toward brake operating position; a train line for supplying pressure to the primary pressure chamber in opposition to the spring; a valve subject to train-line pressure on one side and to primary-chamber pressure on the opposite side, said valve having means controlling communication between the train line and the primary chamber, and between train-line pressure Jfrom a position of small secondary-chamber exhaust towardincreased secondary-chamber exhaust.

16. 1n an air-brake system, a brake cylinder and a brake-controlling piston mounted therein to form primary and secondary pressure chambers on opposite sides of said piston; a springfor normally urging said piston line for supplying pressure to the primary pressure chamber in opposition to the spring a valve subject to train-line pressure on one side and to primary-chamber pressure on the opposite side, said valve having means controlling communication between the train line and the primary chamber, and between the primary chamber and atmosphere, 'and between the primary and secondary chambers, and between the secondary chamber and atmosphere; a spring plunger carried by said valve and arranged to yieldingly oppose movement of said valve by increased trainline pressure from a position of small secondary-chamber exhaust toward increased secondary-chamber exhaust, and a yielding means arranged to yieldingly oppose movement of said valve by primarychamber pressure to the positiono primary-chamber exhaust to atmosphere.

17. 1n an air-brake system, a brake cylinder and a brake-controlling piston mounted therein to Jform primary and secondary prestween the primary and secondary' chambers, and, between the secondary chamber and atmosphere; a spring plunger carried by said valve. and arranged to yieldingly oppose movement of said valve by increased trainline pressure from a position of small secondary-chamber exhaust toward increased secondary chamber exhaust, and a spring plunger carried by said valve and arranged to yieldingly oppose movement of the valve by primary-chamber pressure to the position of primarychamber exhaust to atmosphere, and local exhaust of train-line pressure to atmosphere.

20. 1n an air-brake system, a brake cylinder and a brake controlling piston mounted therein to Jform primary and secondary pressure chambers on opposite sides of said piston; a spring for normally urging said piston toward brake-operating position; a train-line for supplying pressure to the primary pressure chamber in opposition to said spring; a valve subject to train-line pressure on one side and to primar -chamber pressure on the other side, ve having means controlton; a spring for normally urging said piston toward brake operating position; a train line for supplying pressure to the primary pressure chamber in opposition to the spring; on one side and to primary-ch'amber pressure on the opposite side, said valve having means controlling communication between the train line and the primary chamber, and between between the primary and secondary chambers, and between the secondary chamber and atmosphere; a spring plunger carried by said valve and arranged to yieldingly oppose movement of said valve by increased trainline pressure from a position of small secondary-chamber exhaust toward increased secondary-chamber exhaust, and a yielding means arranged to vyieldingly oppose movement of said valve by primary-chamber pressure to the position of primary-chamber exhaust to atmosphere and local exhaust of train-line pressure to atmosphere.

18. 1n an air-brake system, a brake cylinder and a brake-controlling piston mounted therein to jform primary' and secondary pressure chambers on opposite sides of said piston; 'a spring for normally urging said piston toward brakeoperating position; a train line for supplying'pressure to the primary pressure chamber in opposition' to the spring;

said va and the primary-chamber and between the primary-chamber and atmosphere, and' between the primaryV and second ary chambers, and between'tlie secondary-chamber and atmosphere; a local exhaust for train-line; a yielding means arranged to yieldingly opthe primary chamber and atmosphere, and bev ,ling communication' between the train-line pose movement of the said valve by increased train-line pressure from a position of small secon (lary-chamber exhaust toward increased secondarychamber exhaust, and yielding means arranged to yieldingly oppose moveby primary chamber pressure to the position of primary-chamber exhaust to atmosphere and local train-line exhaust.

21. In an air-brake system, a brake cylinder and a brake controlling piston mounted therein to form primary and secondary pressure chambers on opposite sides of said piston; a spring for normally urging said piston toward brake operating position a train-line for supplying pressure to the primary pressure chamber in opposition to said spring; a valve subject to train-line pressure on one side and to primary-chamber pressure on the other side, ling communication between the train-line and the primary-chamber and between the primary-chamber and atmosphere, and between the primary and secondary chambers, and between the secondary-chamber and atmosphere; a local exhaust for train-line; and a pair of oppositely acting spring plungers cariied by said valve, one of said plungers arranged to yieldiiigly oppose movement of the valve by primary-chamber pressure to the position of primary-chamber exhaust to atmosphere and local train-line exhaust, and the other of said plungers arranged to yieldingly oppose movement of said valve by increased train-line pressure from a position of small secondary-chamber exhaust toward iiicreased secondary-chainber exhaust.

22. In an air-brake system, a brake cylinder and a brake-controlling piston mounted therein to form primary and secondary pressure chambers on opposite sides of said piston, a spring for normally urging said piston toward brake-operating position; a train-line for supplying pressure to the primary pressure chamber in opposition to the spring; a valve subject to train-line pressure on one side and primary-chamber pressure on the opposite side, said valve having means controlling communication between the train-line and the primary-chamber, and between the primary-chamber and atmosphere, and between the primary and secondary chambers, and between the secondary-chamber and atmosphere, and a train-line exhaust to atmosphere, and a local exhaust from train-line to a reducing pocket, and from reducing pocket to atmosphere, substantially as and for the purpose set forth.

In an air-brake system, a brake cylinder and a brake-controlling piston mounted therein to form primary and secondary pressure chambers on opposite sides of said piston, a spring for normally urging said piston toward brake-operating position; a train-line l lopposite side, said for supplying pressure to the sure chamber in opposition to valve subject to train-line piessiire on one side and primary-cliamber pressure on the opposite side, said valve having means controlling communication between the train-line and the priinary-cliainber, and between the primary-chamlicr and atmosphere, and between the primary and secondary chambers, and between the secondarf-chamber and atmosphere, and a train-line exhaust to atmosphere, and a local exhaust from train-line to a reducing pocket, and from said reducing pocket to atniospliere, and yielding means arranged to yieldingly oppose movement ol said valve in each direction at opposite ends of its stroke.

24E.- In an air-brake system, a brake cylinder and a brake controlling piston mounted therein to `lorni primary and secondary pressure chambers on opposite sides oi' said piston, a spring 'for normally uiging said piston toward brake-operating position; a trainliiie for supplying pressure to the primary pressure chamber in opposition to the spring; a valve subject to train-line pressure on one side and primary-chaml)er pressure on l he valve having ineanseontrolling communication between the trainliiie and the primary-chamber, and between the primary-chamber and atmosphere, and between thc primary and secondary chainbers, and between the secondary-chamber and atmosphere, and a train-line exhaust to atmosphere, and a local exhaust 'from trainline to a reducing pocket, and from said rcduciiig pocket to atmosphere, and a pair ol" spring plungers carried by said valve and operating in opposite directions to yieldingly oppose movement of said valve at the ends of its stroke.

25. In an air-brake mechanism, the combination, with a double-ended. cylinder, a brake-controlled piston mounted therein to forni primary and secondary pressure chamers, a spring tending to drive the piston to brake-setting position, a train-line-exhaust pocket, and a transfer iassage fi'irming a conimunication between tlie two pressure chambers of a valve mechanism ior controlling the brake-operating piston, anisin comprising the following parts, a valve cylinder communicating with the train-lino at one end and at the other end with the primary pressure chamber, said valve cylinder primary presthe spring; a

iaving a port communicating with the transer passage, a port communicating with atmosphere, a supply port communicati n g with the train line end of the cylinder and a poit leading to the train-line-exhaust pocket; a

piston valve mounted in said valve cylinder .Y

and comprising a head member and a ring member, said ring member having a limited axial play in the head member and said ring said valve meohj i flll lll() member having a passage forming a communlcation between its outer end and its circumference in osition to be brought into register with the `transfer passage port, a pocket in the circumference of said ring member and adapted to be brought into register with the transfer passage portand the atmosphere port, also the ring member to communicate with its interior and at the circumference of the ring adapted to register with the train-line port, and also a ocket adapted to connect the train-line-exliaust pocket with atmosphere, and also a passage adapted to connect the said pocket with the train-line, and a springclosed emergency valve controlling communication between the train line and the secondary pressure chamber, said emergency valve lying in the path of movement of the piston valve.

26. In an air-brake mechanism, the combination, with a double-ended cylinder, a brake-controlled piston mounted therein to form primary and secondary pressure chambers, a spring tending to drive the piston to brake-setting position, a train-line-exhaust pocket, and a transfer passage forming a communication between the two pressure chambers; of a valve mechanism for controlling the brake-operating piston, said valve mechanism comprising the following parts, a valve cylinder communicating with the trainline at one end and at the other end with the primary pressure chamber, said valve cylinder having a port communicating with the transfer passage, a port communicating with,

atmosphere, a supply port communicatin with the train line end of the cylinder an a port leading to the train-line-exhaust pocket; a piston valve mounted in said valve cylinder and comprising a head member and a ring member, said ring member having a limited axial play in the head member and said ring member having a passage forming a communication between its outer end and its circumference in position to be brought into register with the transfer passage port, a pocket in the Vcircumference of said ring member and adapted to be brought into register with the transfer passage port and the atmos here port, also a passage extending throug the ring member to communicate with its interior and at the circumference of the ring ada ted to register with the trainline port, an also a pocket ada ted to connect the train-line-exhaust poc et with at- -mosphere, and also a passage adapted to connect the said pocket with the train-line, and a spring-closed emergency valve controlling communication between the train line and the secondary pressure chamber, said emergency valve lying in the path of movement of the piston valve and the piston a passage extending through i valve cylinder having passages 80-81 forming a communication between the primary pressure chamber `and the train-line when the emergency valve is opened by the piston valve. y

27. In an air-brake, a double-ended brake cylinder having a transfer passage between its ends, a brake-operating piston mounted in said cylinder, a spring yieldingly urging said piston to brake-setting position, and a train-line, of a valve subject to train-line pressure and pressure in the initial end of the brake-cylinder, said valve controlling communication between train-line and the initial end of the cylinder, between the initial end of the cylinder and the transfer passage, and between atmosphere and both the transfer passage and the initial end of the cylinder, yielding means for yieldingly resisting movement of said valve in one direction, and a spring-closed emergency valve arranged in the path of movement of the first mentioned valve and ada ted to control communication between tl3 end of the brake cylinder.

28. In an air brake, a double-ended brake cylinder having a transfer passage between its ends, a brake-operating piston mounted in said cylinder, a spring yieldingly urging said iston tobrake-setting position, and a trainline, of a Valve subject to train-line pressure and pressure in the initial end of the brake-cylinder, said valve controlling communication between vtrain-line and the initial end of the cylinder, between the initial end of the cylinder and the transfer passage, and between atmosphere and both the transfer passage and the initial end of the cylinder, a pair of spring ressed Cplungers projected from opposite en s of sai valve and adapted to engage the casing at the opposite ends of the travel of said valve 'to yieldingly resist further movement thereof in the corresponding direction, an emergency valve arranged to control communication between the train-line and the farther end of the cylinder and also arranged'in the path of movement of one of said spring plungers, and a spring for normally closing said emergency valve, said spring being stronger than the spring of the coperating plunger.

29. An air brake comprising a cylinder and piston, a spring for driving the piston in one direction, and a train-line for supplying pressure to the initial end of said cylinder in opposition to the spring, a valve arranged between the train-line and initial end of the cylinder, said valvecarrying a port-controlling -member, a pair of oppositely acting spring plungers carried by the valve and operating to yieldingly limit the throw of the valve at its o posite ends, an emergency valve arrange to control communication between the train-line and lhe farther end of my hand and seal at lndizrnzrpolis, Indiana, the cyhnder and also arranged 1n the path of thls twentleth day ol' November, A. l). one movement of one of Saud sprlng plungers, thousand lune hundred :nul seven.

and a spring for normally closing said e1ner- AUGUSTUS A. S'l. CLAIR. I L. 5 gency Velve, sard Spring being stronger than VVltnossos:

the sp1-lng of the oo erating plunger. ARTHUR M. HOOD,

In Witness Whereo I, have hereunto set THOMAS MCMEANS 

